KR100870387B1 - Extrusion Coated Substrate - Google Patents

Abstract

The present invention two or more C _{4 -12} alpha as comonomers for, and ethylene comprising a polyethylene produced by polymerization catalysed by a single site catalyst - relates to an extrusion coated substrate having a coating comprising an olefin .

Extrusion, Coating, Polyethylene Composition, Bimodal Single Site, LDPE

Description

Extrusion Coated Substrate

The present invention relates not only to the method of extrusion coating a substrate with a polyethylene composition, but also to the extrusion coated structure itself.

More specifically, the present invention relates to the use of certain bimodal single site polyethylenes in extrusion coating.

Low density polyethylene (LDPE), typically produced in high pressure radical processes, preferably in autoclave reactors, has been used for extrusion coating for many years. In extrusion coating, the polymer resin is formed into a molten, thin, hot film, which is typically coated on a moving planar substrate such as paper, cardboard, metal foil, or plastic film. The coated substrate then passes between a set of counter rotating rollers, compressing the coating onto the substrate to ensure complete contact and adhesion.

Polymers used in extrusion coating need to have certain properties in order to be useful as coatings. For example, the coating should provide a suitable moisture barrier and exhibit good sealing properties, which should also have the necessary mechanical properties and high temperature viscosity. In this respect, LDPE does not have the ideal mechanical properties required by extrusion coatings since they are not rigid and lead resistant. Accordingly, it is known to blend LDPE with other polymer grades to improve mechanical properties.

Thus, LDPE has previously been used in conjunction with higher density polyethylenes such as medium or high density polyethylene or linear low density polyethylene to improve mechanical properties. For example, small amounts of LDPE (5-30% by weight) may be added to the LLDPE to improve the processability of the extrusion coating composition. However, when the content of LDPE in the composition increases, useful properties of the linear polymer, such as environmental stress crack resistance, barrier properties and sealing properties, are soon diluted or lost. On the other hand, the LDPE content is too low and the blend may not have sufficient processability. The problem with such low LDPE content blends is that while the blends have better processability than LLDPE alone, they may not be extruded or drawn at high take-off rates. Therefore, a balance between good mechanical properties and good workability is required.

Linear low density polyethylene (LLDPE) and ultra low density polyethylene (ULDPE) extrusion compositions commonly prepared using Ziegler-Natta catalysis improve mechanical strength, but are also difficult to process due to lack of extrudability.

Thus, there is still a need to invent additional polyethylene polymer compositions suitable for extrusion coating that provide both good mechanical properties and processability.

International Publication No. WO01 / 62847 proposes a solution to this problem by using a bimodal polyethylene composition prepared using a single site catalyst in a multistage process. The composition can be used as the extrusion coating itself or mixed with trace amounts of LDPE prior to the extrusion process. The polymer thus produced is preferably a bimodal ethylene / butene copolymer in which butene is used in both the circulation stage and the gas phase stage of the two stage process.

While the polymers described in WO 01/62847 have acceptable seal initiation temperatures and relatively wide sealing windows, their high temperature viscosity strengths are limited. In this respect, hexene-ethylene copolymers are known to provide superior sealing properties than butene-ethylene copolymers, and octene-ethylene copolymers are known to provide superior properties than hexene-ethylene copolymers.

However, the use of higher alpha-olefin comonomers, ie, alpha-olefins greater than C ₆ , increases the cost of the polymer product and generally decreases the incorporation efficiency of the comonomer as the comonomer increases in carbon number, ie hexene It is incorporated at lower efficiency than butene and octene is incorporated at lower efficiency, such as hexene. Thus, the skilled person does not prefer to include higher monomers.

By incorporating two different alpha-olefin comonomers, the inventors have found that a multimodal polyethylene composition ideal for extrusion coating having superior sealing properties and high temperature viscosity than polyethylene produced using one of the comonomers as a single comonomer It has been found that, for example, bimodal polyethylene compositions can be prepared.

When, as seen from one aspect, the present invention provides an extrusion coated substrate, that is produced by polymerization catalysed by a single site catalyst and as a comonomer for ethylene alpha _-12 of two or more C ₄ - is the olefin, preferably But-1-ene, hex-1-ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and deck-1-ene, particularly preferably but-1-ene and Provided is a coating comprising a polyethylene comprising at least two alpha-olefins selected from the group consisting of hex-1-ene.

As viewed from another aspect, the present invention is produced by polymerization catalysed by a single site catalyst for the formation of cast film or extrusion coating of two or more as comonomers for the ethylene-C _{4 -12} alpha-olefins to, preferably Is but-1-ene, hex-1-ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and deck-1-ene, particularly preferably but-1-l-ene And two or more alpha-olefins selected from the group consisting of hex-1-ene.

In many cases, the sealant formed between the sealed surfaces is subjected to a load in the warmed state. This means that the high temperature viscosity properties of the polyethylene are important to ensure that they form a strong seal even before cooling. All extrusion coatings have a window in which a seal is formed, that is, a window in which the extrudate partially melts. Typically, such a sealing window has a rather narrow meaning that temperature control is important during the heat sealing process. The polymers of the present invention allow a wider sealing window to ensure that the sealing operation occurs at lower temperatures and that temperature control is less important during heat sealing. By operating at lower temperatures, there is an advantage that the sealed item is not exposed to high temperatures and any other components of the extrusion coating that may not be involved in sealing are not exposed to high temperatures. Of course, lower temperatures are also economically advantageous as they are less expensive to produce and maintain.

The polyethylene of the extrusion coating of the present invention is typically a mixture of two or more polyethylenes, for example polyethylene produced by blending or two or more stages of polymerization. The polyethylene component may be a homopolymer, copolymer, trimer or polymer of at least 4 comonomers, but preferably at least one polymer is a trimer and at least two polymers are copolymers, in particular one which is the main component The monomer of is ethylene, and one or two comonomers which are a hydrophobic component are C ₄ and / or C ₆ alpha-olefins.

The polymer in two or more stages of polymerization, in which a lower alpha-olefin comonomer (eg, but-1-ene) is incorporated in the initial stage and a higher alpha-olefin comonomer (hex-1-ene) is incorporated in the later stage. It is particularly preferred that is produced. Nevertheless, the ethylene homopolymer is produced in the first stage and the ethylene trimer is produced in the second stage or vice versa, or the ethylene copolymer with the higher alpha-olefin comonomer is produced in the first stage and the second It is within the scope of the present invention to produce the polymer in a two stage polymerization in which the ethylene copolymer having the lower alpha-olefin comonomer is produced in the stage.

In the most preferred embodiment, the polyethylene is an ethylene / but-1-ene copolymer (low molecular weight component) preferably prepared in a slurry phase and an ethylene / hex-1-ene copolymer preferably prepared in a gas phase. It is formed from a mixture of (high molecular weight components).

The term "monopolymer" of ethylene as used herein is substantially, for example, at least 98% by weight, preferably at least 99% by weight, more preferably at least 99.5% by weight and most preferably at least 99.8% by weight of ethylene units. Refers to a polyethylene consisting of.

Ethylene polymers of the present invention are prepared using so-called single site catalysts, for example catalysts comprising metals coordinated by one or more η-binding ligands. Such η-bonded metals are commonly referred to as metallocenes, which are typically Zr, Hf or Ti, in particular Zr or Hf. The η-binding ligand is typically a η ⁵ -cyclic ligand, ie a homo or heterocyclic cyclopentadienyl group optionally having a fusion or accessory substituent. Such metallocene catalysts have been widely disclosed in the scientific and patent literature for about 20 years. Such metallocene catalysts are often used with catalytically active agents or cocatalysts, for example alumoxanes such as methylaluminoxane, which are widely disclosed in the literature.

The polymer used in the extrusion coating of the invention is preferably multimodal, for example bimodal, ie its molecular weight profile does not comprise a single peak, but instead the polymer is two or more independent. Due to the fact that it contains components produced, it includes a combination of two or more peaks, which may be distinguishable or indistinguishable, concentrated at approximately different average molecular weights.

In this embodiment, the high molecular weight component preferably corresponds to the copolymer (or trimer, etc.) of the higher alpha-olefin comonomer, and the low molecular weight component preferably is an ethylene homopolymer, or the lower alpha-olefin. Corresponds to the copolymer (or trimer, etc.) of the comonomer. Such bimodal ethylene polymers can be produced, for example, by two or more stages of polymerization, or by using two or more different polymerization catalysts in one stage of polymerization. However, they are preferably produced in a gas phase polymerization in a gas phase reactor after a two stage polymerization, in particular in a circulating reactor, after slurry polymerization using the same catalyst, for example a metallocene catalyst. The circulating reactor-gas reactor system was developed by Borealis A / S from Denmark and is known as the BORSTAR ^® technique.

Preferably, the low molecular weight polymer fraction is produced in a continuously operating circulating reactor in which ethylene is polymerized in the presence of a polymerization catalyst as described above and a chain transfer agent such as hydrogen. The diluent is typically an inert aliphatic hydrocarbon, preferably isobutane or propane. C ₄ to C ₁₂ alpha-olefin comonomers are preferably added to control the density of the low molecular weight copolymer fraction.

Preferably, the hydrogen concentration is chosen such that the low molecular weight copolymer fraction has the desired melt flow rate. More preferably, the molar ratio of hydrogen to ethylene is between 0.1 mol / kmol and 1.5 mol / kmol, most preferably between 0.2 mol / kmol and 1.0 mol / kmol.

When the target density of the low molecular weight copolymer fraction exceeds 955 kg / m 3, the propane diluent under so-called supercritical conditions in which the operating temperature exceeds the critical temperature of the reaction mixture and the operating pressure exceeds the critical pressure of the reaction mixture. It is advantageous to operate the circulation reactor using The preferred temperature range is then 90 to 110 ° C. and the pressure range is 50 to 80 bar.

The slurry is removed intermittently or continuously in the circulation reactor and is sent to separation means where at least the chain transfer agent (eg hydrogen) is separated from the polymer. The polymer containing the active catalyst is then introduced into a gas phase reactor where the polymerization proceeds in the presence of additional ethylene, comonomer (s) and optionally a chain transfer agent to produce a high molecular weight copolymer fraction. Is introduced. The polymer is recovered intermittently or continuously from the gas phase reactor and the remaining hydrocarbons are separated from the polymer. The polymer collected from the gas phase reactor is a polyethylene composition of the present invention.

The conditions of the gas phase reactor are chosen such that the ethylene polymer has the desired properties.

Preferably, the temperature in the reactor is 70 to 100 ° C. and the pressure is 10 to 40 bar. The molar ratio of hydrogen to ethylene is preferably 0 to 1 mol / kmol, more preferably 0 to 0.5 mol / kmol, and the molar ratio of the alpha-olefin comonomer to ethylene is preferably 1 to 100 mol / kmol, more preferably Is in the range from 5 to 50 mol / kmol, most preferably from 5 to 30 mol / kmol.

The extrusion coating process can be carried out using conventional extrusion coating techniques. As a result, the polymer obtained from the polymerization process is fed to the extruder, typically in the form of pellets, optionally comprising additives. From the extruder, the polymer melt is passed through a planar die to a coated substrate. Due to the distance between the die lip and the nip, the molten plastic is oxidized in the atmosphere for a short period of time, generally improving the adhesion between the coating and the substrate. The coated substrate is cooled on a chill roll, which is then transferred to an edge trimmer and wound up. The width of the line may, for example, range from 500 to 1,500 mm, for example from 800 to 1,100 mm, with a line speed of up to 1,000 m / min, for example 300 to 800 m / min. The temperature of the polymer melt is typically from 275 to 330 ° C.

The multimodal polyethylene composition of the present invention may be extruded onto a substrate as a single layer coating or as one layer in coextrusion. In one of these cases, the multimodal polyethylene composition may be compatible as such, or the blend is 0 to 50%, preferably 10 to 40%, particularly preferably 15 to 15, based on the weight of the final blend. The multimodal polyethylene composition can be blended with other polymers, in particular LDPE, to contain 35% LDPE. Blending can be carried out in a post-reactor treatment in the coating process or prior to extrusion.

In a multilayer extrusion coating, the other layers can include any polymeric resin with the desired properties and processability. Examples of such polymers include barrier layer PA (polyamide) and EVA; Polar copolymers of ethylene, such as copolymers of ethylene and vinyl alcohol, or copolymers of ethylene and acrylate monomers; Adhesive layers such as ionomers, copolymers of ethylene and ethyl acrylate, and the like; HDPE for hardness; Polypropylene for improving heat resistance and grease resistance; LDPE resin produced in the high pressure process; LLDPE resins produced by polymerizing ethylene and alpha-olefin comonomers in the presence of a Ziegler, chromium or metallocene catalyst; And MDPE resins.

In a preferred embodiment, the polymer is blended with LDPE, which LDPE preferably has a melt flow rate of at least 3 g / 10 minutes, preferably at least 6.5 g / 10 minutes and is designed for extrusion coating. The LDPE may form 15 to 35% by weight of the final blend. The blend may be coated as a monolayer on the substrate or may be coextruded with other polymer (s) as known in the art.

The substrate is preferably a fibrous material such as paper or cardboard. The substrate may also be a film made of polyester, cellophane, polyamide, polypropylene or oriented polypropylene, for example. Other suitable substrates include aluminum foil.

The coating will typically have a thickness of 10 to 1,000 μm, in particular 20 to 100 μm. The particular thickness will be selected depending on the nature of the substrate and its expected subsequent processing conditions. The substrate may have a thickness of 10 to 1,000 μm, for example 6 to 300 μm.

When viewed from a further aspect, the invention also provides a polyethylene composition for extrusion coating wherein the composition comprises two or more kinds are produced by polymerization catalysed by a single site catalyst as a comonomer for ethylene C _{4 -12} alpha - Olefins, preferably but-1-ene, hex-1-ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and deck-1-ene, in particular but-1- Polyethylenes having two or more alpha-olefins selected from the group consisting of ene and hex-1-ene.

When viewed from a further aspect, the present invention provides two or more thereof as comonomers to ethylene is produced by polymerization catalysed by a single site catalyst C _{4 -12} alpha-olefins, preferably 1-ene, hex--1 2 kinds selected from the group consisting of -ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and deck-1-ene, in particular but-1-ene and hex-1-ene Extruding polyethylene comprising at least alpha-olefins to form a polymer melt; And it provides an extrusion coating method of the substrate comprising the step of coating the substrate with the melt.

Extrusion coating of the present invention is preferably,

a) low molecular weight copolymer of ethylene and but-1-ene; And

b) a bimodal trimer comprising a high molecular weight copolymer of ethylene and a C ₅ to C ₁₂ alpha-olefin (eg, C ₆ to C ₁₂ alpha-olefin),

a ') a low molecular weight polymer which is a bicomponent copolymer of ethylene and C ₄ to C ₁₂ alpha-olefins; And

b ') Ethylene and but-1- when the low molecular weight polymer of component a') is a bicomponent copolymer of ethylene and C ₅ to C ₁₂ alpha-olefins (eg C ₆ to C ₁₂ alpha-olefins) Bimodal polymers comprising high molecular weight polymers that are two-component copolymers of ene or trimers of ethylene, but-1-ene and C ₅ to C ₁₂ alpha-olefins (eg, C ₆ to C ₁₂ alpha-olefins) It includes.

In a preferred embodiment, the present invention provides a coating of bimodal polymers having a relatively narrow molecular weight distribution (MWD), good sealing properties, good processability, low water vapor permeability and low levels of extractability. The MWD is preferably 2.5 to 10, in particular 3.0 to 6.0.

The weight average molecular weight of the multimodal, eg bimodal polymer is preferably 50,000 to 250,000 g / mol. The low molecular weight polymer fraction preferably has a weight average molecular weight of 5000 to 100,000 g / mol, more preferably 10,000 to 70,000 g / mol, and the high molecular weight polymer fraction is preferably 50,000 to 500,000 g / mol, more Preferably it has a weight average molecular weight of 100,000 to 300,000 g / mol.

The molecular weight distribution of the polymer is further characterized by its melt flow rate (MFR) according to ISO 1133 at 190 ° C. The final multimodal, for example bimodal polymer preferably has a melt flow rate (MFR ₂ ) of 1 to 30 g / 10 minutes, more preferably 5 to 25 g / 10 minutes. The low molecular weight polymer fraction preferably has a melt flow rate (MFR ₂ ) of 5 to 1,000 g / 10 minutes, more preferably 10 to 200 g / 10 minutes.

The density of the polymer is preferably 905 to 940 kg / m 3, more preferably 905 to 935 kg / m 3. The density of the low molecular weight polymer fraction is preferably 920 to 950 kg / m 3, more preferably 925 to 940 kg / m 3. The density of the high molecular weight component polymer fraction is preferably 880 to 910 kg / m 3, more preferably 895 to 905 kg / m 3. The low molecular weight component should have a higher density than the high molecular weight component.

The seal initiation temperature can be adjusted by adjusting the MFR of the polymer and the density of the low molecular weight component. Higher MFR can lower the seal initiation temperature. In a very preferred embodiment, the polymers of the present invention maintain a constant heat seal over a wide temperature range. As a result, the heat sealing force is substantially constant, for example the sealing force is within 2N / 25.4 mm, preferably within 1N / 25.4 mm over a temperature range of 30 ° C. or higher, preferably 40 ° C. or higher. These characteristics are shown in FIGS. 1 and 2.

The bimodal polymer according to the invention preferably comprises 30 to 70% by weight, more preferably 35 to 60% by weight, most preferably 38 to 55% by weight, based on the total composition of the low molecular weight copolymer fraction. Include.

The total comonomer content in the polymer is preferably 0.5 to 10 mol%, preferably 1.5 to 6.5 mol%, more preferably 2 to 5 mol%, and the comonomer content in the low molecular weight polymer is preferably 0 to 2.0 mol%, preferably 0.5 to 1.5 mol%. In the high molecular weight polymer, the comonomer content is preferably 1.5 to 8 mol%, preferably 3.5 to 6 mol%. Comonomer content can be measured by NMR.

The melting point of the polymer is 100 to 130 ° C, preferably 110 to 120 ° C.

In addition, the molecular weight of the high molecular weight copolymer fraction should be chosen such that the final bimodal polymer has the melt flow rate and density as described above where the low molecular weight copolymer fraction has the melt flow rate and density described above.

In addition to the polymers themselves, the coatings of the present invention may also contain antioxidants, process stabilizers, pigments and other additives known in the art. In addition, the multimodal single site catalytic ethylene polymer, along with two other alpha-olefin comonomers, can be blended with other polymers while maintaining the sealing and mechanical properties suitable for the desired end use. Examples of such additional polymers that may be used include LDPE, HDPE, MDPE, LLDPE, EMA, EBA and EVA. Typically, up to about 50% by weight total polymer may be constituted by a large amount of additional polymers, and more preferably up to 30% by weight in the case of HDPE, MDPE or LLDPE. The multimodal single site catalyst ethylene polymer can be used in combination with two other alpha-olefin comonomers to produce a film on a cast film process.

Presently, the present invention will be further described with reference to the following non-limiting examples and the accompanying drawings showing the heat sealing properties of the various examples below.

1 is a graph showing the heat sealing characteristics of Examples 3 to 8,

2 is a graph showing heat sealing characteristics of Examples 9 to 14. FIG.

Experimental Example :

Melt flow rate according to ISO 1133 at 190 ° C. (MFR, often referred to as melt index). The load used for the measurement is shown as a subscript, ie MFR ₂ represents the NFR measured under 2.16 kg load.

The molecular weight average and molecular weight distribution were measured by size exclusion chromatography (SEC) using a Waters Alliance GPCV2000 instrument equipped with an on-line viscometer. Oven temperature was 140 ° C. Trichlorobenzene was used as the solvent.

Density was measured according to ISO 1183-1987.

The but-1-ene and hex-1-ene contents of the polymers were determined by ¹³ C NMR.

The basis weight was determined as follows: Five samples from the extrusion coated all day were cut in parallel in the row direction of the process line. The sample is 10 cm × 10 cm in size. After soaking the sample in the solvent for 10-30 minutes, the paper is removed from the plastic and the solvent is evaporated. The sample is then weighed and averaged. The results are shown as the weight of the plastic per square meter.

When the paper substrate has a constant basis weight, the measurement may be performed without removing the paper. In this case the basis weight of the paper was subtracted from the measured basis weight. The difference was recorded as a result.

Rheometrics RDA II Dynamic Rheometer was used to measure the flow characteristics of the polymer. The measurement was carried out at 190 ° C. under a nitrogen atmosphere. The measured values represent the storage modulus (G ') and the loss modulus (G ") together with the absolute value (η *) of the composite viscosity or the absolute value (G *) of the composite modulus as a function of frequency (ω).

According to the Cox-Merz rule, when the frequency is expressed in units of rad / sec, the composite viscosity function η * (ω) is the same as a conventional viscosity function (viscosity as a function of shear rate). If this experimental equation is valid, the absolute value of the composite modulus corresponds to the shear stress in conventional (ie steady state) viscosity measurements. This means that the function η * (G *) is equal to the viscosity as a function of the shear stress.

In the process of the invention, both the viscosity at low shear stress or η * at low G * (which acts as approximately so-called zero viscosity), and the zero shear rate viscosity, were used as a side chain of average molecular weight. On the other hand, shear thinning, which is a decrease in viscosity with G *, becomes more apparent as the molecular weight distribution becomes larger. This property can be approximated by defining the so-called shear thinning index (SHI) as the ratio of the viscosity at two different shear stresses. In the examples below, shear stresses (or G *) of 0 and 100 kPa were used. therefore,

Where η * ₀ is the zero shear rate viscosity and η * ₁₀₀ is the composite viscosity at G * = 100 kPa.

As mentioned above, the storage modulus function G * (ω) and the loss modulus function G "(ω) were obtained as a first order function from the dynamic measurements. At a particular value of the loss modulus, the value of the storage modulus is the molecular weight distribution. Increases with increasing, but this amount is highly dependent on the shape of the molecular weight distribution of the polymer. In the examples, the value of G 'at G "= 5 was used.

Melting point and crystallinity were measured by differential scanning calorimetry (DSC) using Mettler Toledo DSC822 at a heating and cooling rate of 10 ° C./min.

catalyst Production Example  One:

134 g of metallocene complex (bis (n-butyldicyclopentadienyl) hafnium chloride (containing 0.36 wt.% Hf) provided as TA02823 by Witco) and 9.67 kg of methylalumoxane (MAO) in toluene 30% solution (provided by Albemarle) was combined and 3.18 kg of dried and purified toluene was added. The composite solution thus obtained was added onto Sylopol 55 SJ, a 17 kg silica carrier prepared by Grace. The complex was fed very slowly by uniformly spraying for 2 hours. The temperature was kept below 30 ° C. After the complex was added at 30 ° C., the mixture was reacted for 3 hours. The solid catalyst thus obtained was dried and recovered by purging with nitrogen at 50 ° C. for 3 hours.

catalyst Production Example  2:

Benzylpotassium Benzyl Potassium  By using synthesis (n- BuCp ) ₂ HfCl ₂ of Benzylation

First, 200 mmol of potassium t-butoxide (Fluka 60100, 97%) was dissolved in 250 mL of toluene. Then 200 mmol of n-butyllithium (about 2.5M solution in hexane, Aldrich) were added over 1.5 hours. The mixture turned from white to red. The mixture was stirred for 2.5 days. It was then filtered and washed with toluene (5 x 100 mL) and pentane (50 mL). As a result, 21.7 g of benzyl potassium was obtained as a red brick toluene insoluble solid. Yield 83%.

¹ H-NMR in THF-d ₈ , δ (ppm): 6.01 (m, 2H), 5.10 (d, 2H), 4.68 (t, 1H), 2.22 (s, 2H). For chemical shifts see solvent signal at 3.60 ppm. ¹³ C-NM in THF-d ₈ , δ (ppm): 152.3, 129.4, 110.1, 94.3, 51.6. For chemical shifts see solvent signal at 66.50 (medium peak).

(n- BuCp ) ₂ Hf ( CH ₂ Ph ) ₂ Synthesis of

6.87 mmol of bis (n-butylcyclopentadienyl) hafnium chloride and 150 mL of toluene were mixed at 20 ° C. to obtain an off-brown solution. Then, 14.74 mmol of benzyl potassium prepared as described above was added to the solution at 0 ° C. over 10 minutes as a solid. The cooling bath was removed and the mixture was stirred at 20 ° C. for 3 hours.

The solvent was removed under reduced pressure and the remainder was extracted with 3 x 30 mL of pentane. The solvent was removed from the combined pentane solution to yield 3.86 g of (n-BuCp) ₂ Hf (CH ₂ Ph) ₂ as a yellow liquid (yield: 93%).

¹ H-NMR in toluene-d ₈ , δ (ppm): 7.44 (t, 4H), 7.11 (d, 4H), 7.08 (t, 2H), 5.75 (m, 4H), 5.67 (m, 4H), 2.33 (t, 4H), 1.77 (s, 4H), 1.54 (m, 4H), 1.43 (m, 4H), 1.07 (t, 6H). For chemical shifts see solvent signal at 2.30 (middle peak) (middle peak). ¹³ C-NMR in toluene-d ₈ , δ (ppm): 152.7, 137.5, 128, 126.8, 121.6, 112.7, 110.5, 65.3, 34.5, 29.7, 22.8, 14.1. For chemical shifts see solvent signal at 20.46 (middle peak) (middle peak).

Component Analysis: C 63.57% (calculated 63.72), H 6.79% (calculated: 6.68), Hf 29.78% (calculated: 29.59), K <0.1% (calculated: 0)

Catalyst Support and Activation

134 g of (n-BuCp) ₂ HfCl ₂ is substituted with 164 g of (n-BuCp) ₂ Hf (CH ₂ Ph) ₂ prepared as described above and SP9-391 (provided by Grace) as a silica carrier Except for the use, the metallocene was supported and activated as in Catalyst Preparation Example 1.

Example  One:

A continuously operating circulating reactor having a volume of 500 dm 3 was operated at a temperature of 85 ° C. and a pressure of 60 bar. The ethylene concentration in the liquid phase of the reactor is 7 mol%, the ratio of hydrogen to ethylene is 0.65 mol / kmol, the ratio of but-1-ene to ethylene is 155 mol / kmol, and the polymer production rate in the reactor is 25 kg / hour. To the reactor was introduced propane diluent, ethylene, butl-ene comonomer, hydrogen, and a polymerization catalyst prepared according to Catalyst Preparation Example 1. The polymer thus formed had a melt flow rate (MFR ₂ ) of 100 g / 10 min and a density of 935 kg / m 3.

The slurry was intermittently recovered from the reactor by using a settling leg and sent to a flash tank operated at a temperature of about 50 ° C. and a pressure of about 3 bar.

From the flash tank, powder containing small amounts of residual hydrocarbons was transferred to a gas phase reactor operated at a temperature of about 75 ° C. and a pressure of about 20 bar. In addition, the ethylene concentration in the circulating gas is 22 mol%, the ratio of hydrogen to ethylene is about 0.5 mol / kmol, the ratio of hex-l-ene to ethylene is 12 mol / kmol, and the polymer production rate is 26 kg / hour. An additional ethylene, hex-1-ene comonomer, and nitrogen were introduced into the gas phase reactor in amounts. The concentration of butl-ene is so low that it may not be detected by on-line gas chromatography used to monitor the gas composition.

The polymer collected from the gas phase reactor was stabilized by adding 400 ppm Irganox B561 to the powder. The stabilized polymer was then extruded and pelletized under a nitrogen atmosphere using a CIM90P extruder manufactured by Japan Steel Works. Melting temperature was 200 ° C., throughput was 280 kg / hour, and specific energy input (SEI) was 200 kWh / t.

Thus, the production split between the circulation reactor and the gas phase reactor was 49/51. The polymer pellets have a melt flow rate (MFR ₂ ) of 2.7 g / 10 min, a density of 920 kg / m 3, a boot-1-ene content of 2.1 wt%, a hex-1-ene content of 6.3 wt%, The weight average molecular weight (Mw) was 90,600 g / mol, the number average molecular weight (Mn) was 16,200 g / mol, and the z-average molecular weight (M _z ) was 226,000 g / mol. Additionally, the polymer had a zero shear rate viscosity (η ₀ ) of 3630 Pa · s and a shear thinning index (SHI _0/100 ) of 4.1.

Example  2:

The method of Example 1 was repeated except that the process conditions were adjusted as shown in Tables 1-1 and 1-2. The polymer properties are shown in Tables 1-1 and 1-2.

Example  3:

The method of Example 1 was repeated except that the process conditions were adjusted as shown in Tables 1-1 and 1-2. The polymer properties are shown in Tables 2-1 and 2-2.

Example  4:

The method of Example 1 was repeated except that the process conditions were adjusted as shown in Tables 1-1 and 1-2. The polymer was collected as a powder without pelleting. The polymer properties are shown in Tables 2-1 and 2-2.

Example  5:

The method of Example 4 was repeated except that the process conditions were adjusted as shown in Tables 1-1 and 1-2. Prior to pelletizing the powder, 15% CA8200, manufactured and commercially available as LDPE polymer for extrusion coating by Borealis, with an MFR ₂ of 7.5 g / 10 min and a density of 920 kg / m 3, was added to the polymer. The polymer properties shown in Tables 2-1 and 2-2 are measured using powders.

Example  6:

The method of Example 1 was repeated except that a catalyst was prepared according to Preparation Example 2 and the process conditions were adjusted as shown in Tables 1-1 and 1-2. The powder obtained was then dry blended with 12% CA8200 and extruded as described in Example 1. Analytical data is shown in Tables 2-1 and 2-2. Molecular weight, crystallinity and comonomer content were measured using powders, while morphological properties were measured using blends.

Example  7:

The method of Example 6 was repeated except that the process conditions were adjusted as shown in Tables 1-1 and 1-2. No LDPE was added to the polymer. The analytical data is shown in Tables 2-1 and 2-2.

Example  8:

The method of Example 6 was repeated except that the process conditions were adjusted as shown in Tables 1-1 and 1-2. A portion of the powder was then recovered and extruded as described in Example 1. No LDPE was added to the polymer. The analytical data is shown in Tables 2-1 and 2-2.

Example  9:

The method of Example 6 was repeated except that the process conditions were adjusted as shown in Tables 1-1 and 1-2. In addition, some of the powder obtained was recovered, dry blended with 9% of CA8200 and then extruded as described in Example 6. Analytical data of the blends is shown in Tables 2-1 and 2-2.

Example  10:

A portion of the powder of Example 8 was dry blended with 13% CA8200 and then extruded as described in Example 6. Analytical data of the blends is shown in Tables 2-1 and 2-2.

Example  11:

A portion of the powder of Example 8 was dry blended with 24% CA8200 and then extruded as described in Example 6. Analytical data of the blends is shown in Tables 2-1 and 2-2.

Example  12:

The method of Example 6 was repeated except that the temperature of the gas phase reactor was 80 ° C., the operating conditions were different as listed in Tables 1-1 and 1-2, and the amount of LDPE was 10% by weight. Analytical data of the polymers are listed in Tables 2-1 and 2-2. Molecular weight, crystallinity and comonomer content were measured using a powder while morphological properties were measured using the blend.

Example  13:

The method of Example 12 was repeated except that the operating temperature was listed in Tables 1-1 and 1-2 and the amount of LDPE was 25% by weight. Analytical data of the polymers are listed in Tables 2-1 and 2-2. Molecular weight, crystallinity and comonomer content were measured using powder, while morphological properties were measured using the blend.

Example  14:

The method of Example 12 was repeated except that the operating temperature was as listed in Tables 1-1 and 1-2 and the amount of LDPE was 30% by weight. Analytical data of the polymers are listed in Tables 2-1 and 2-2. Molecular weight, crystallinity and comonomer content were measured using a powder while morphological properties were measured using the blend.

Comparative example  One:

Polymers manufactured and sold by Dow under the trade name Affinity PT1451 were used for coating experiments.

Comparative example  2:

Polymers manufactured and sold by Borealis under the trade name CA8200 were used for coating experiments. The polymer had an MFR ₂ of 7.5 g / 10 min and a density of 920 kg / m 3.

Comparative example  3 (international public publication system WO  Manufactured according to 02/02323):

The continuously operated circulation reactor with a volume of 500 d 3 was operated under a temperature of 85 ° C. and a pressure of 60 bar. The ethylene concentration in the liquid phase of the circulator reactor is 6.6 mol%, the ratio of hydrogen to ethylene is 0.63 mol / kmol, the ratio of but-1-ene to ethylene is 183 mol / kmol, and the polymer production rate in the reactor is 25 kg / hour. To this amount, propane diluent, ethylene, but-1-ene comonomer, hydrogen, and polymerase prepared according to Catalyst Preparation Example 1 were introduced into the reactor. The polymer thus formed had a melt flow rate (MFR ₂ ) of 120 g / 10 min and a density of 936 kg / m 3.

The slurry was intermittently recovered from the reactor by using a fixed foot and sent to a flash tank operated at a temperature of about 50 ° C. and a pressure of about 3 bar.

From the flash tank, powder containing small amounts of residual hydrocarbons was transferred to a gas phase reactor operated at a temperature of about 75 ° C. and a pressure of about 20 bar. In addition, the ethylene concentration in the circulating gas is 23 mol%, the ratio of hydrogen to ethylene is about 1.2 mol / kmol, the ratio of butl-ene to ethylene is 48 mol / kmol, and the polymer production rate is 26 kg / hour. Introduce additional ethylene, but-1-ene comonomer, and nitrogen as inert gas to the gas phase reactor. Thus, the production distribution was 49/51. No hex-1-ene was introduced into the gas phase reactor.

The polymer collected from the gas phase reactor was stabilized by adding 400 ppm Irganox B561 to the powder. The stabilized polymer was then extruded and pelletized under a nitrogen atmosphere using a CIM90P extruder manufactured by Japan Steel Works. Melting temperature was 200 ° C., throughput was 280 kg / hour, and specific energy input (SEI) was 200 kWh / t.

The production distribution between the circulation reactor and the gas phase reactor was 49/51. The polymer pellets have a melt flow rate (MFR ₂ ) of 10 g / 10 min, a density of 916 kg / m 3, a boot-1-ene content of 8.1 wt%, a weight average molecular weight (Mw) of 67,800 g / mol, water The average molecular weight (Mn) was 19,600 g / mol and the z-average molecular weight (M _z ) was 140,000 g / mol. Additionally, the polymer had a zero shear rate viscosity (η ₀ ) of 800 Pa · s and a shear thinning index (SHI _0/100 ) of 2.4.

Example  15:

The polymer powder produced in Example 4 was dry blended with CA8200 and Irganox B561 so that the amount of CA8200 was 15% by weight relative to the total composition and the amount of Irganox B561 was 400 ppm. The resulting blend was extruded and pelletized in a nitrogen atmosphere using a Berstorff BZE40A extruder so that the yield was 40 kg / hour and the melting temperature was 195 ° C.

Example  16:

Extrusion coating operations were performed on a Beloit coextrusion coating process line. The process line is equipped with a Peter Cloeren die and a five-layer feed block. The width of the process line was 850-1000 mm and the maximum process speed was 1,000 m / min (design value).

In the coating process line, based on a weight of 70g / m ₂ of UG kraft paper (kraft) based on the paper weight of 6g / m ₂ of CA8200 layer, and a basis weight of a present manufacture from 26g / m ₂ of Examples 1 to 9 Coated with the inventive polymer composition layer. The temperature of the polymer melt was set at 300 ° C. The process speed was 100 m / min.

Example  17:

Extrusion coating operations were performed according to Example 16, except that monolayer coatings were produced at different process rates. The highest process speed was recorded showing stable behavior.

Single layer coatings were prepared from the materials such that the basis weight was 10 g / m ₂ . The data is shown in Table 3.

The term “no” means that the behavior is so unstable at a process speed of 400 m / min or more that the coating can no longer be analyzed. N.D. indicates no measurement of individual samples.

The column maximum rpm represents the maximum rpm value of the extruder motor when producing the coating. The higher the value, the better the processability and the higher the yield of the polymer.

The column maximum process speed represents the maximum process speed of the web in m / min. Low maximum process speeds indicate that the resin tends to undergo a draw resonance that causes the polymer flow from the die to begin to vibrate violently, resulting in an uneven coating. The higher the value, the better the performance of the polymer on the coating process line and the higher the production rate of the coating.

The weight of the column coating represents the measured coating weight and the range in which the coating weight varies. The condition is not optimized to minimize changes.

Example  18:

High temperature viscosity tests were performed on the coatings produced in Example 16 to determine the sealability. Samples (coated side to coated side) were folded and pressed together at elevated temperature. Sealing time was 0.5 second, lag time was 0.2 second, and sealing pressure was 1.5 N / mm <2> in the test piece of 15 mm width. Next, the force to break the sealing material was measured. The data is shown in the accompanying drawings.

Discussion: What can be seen from the above examples and comparative examples is as follows:

The polymer of Comparative Example 1 has very good sealing properties but its workability is poor as indicated by the low maximum RPM values in Table 3.

The polymer of Comparative Example 2 has poor sealing properties, but its workability is very good.

The polymers of Examples 1 to 14 have a combination between good sealing properties and processability.

It relates to an extrusion coated substrate having a coating comprising an olefin-the invention two or more C _{4 -12} alpha as comonomers for, and ethylene comprising a polyethylene produced by polymerization catalysed by a single site catalyst There is an effect of having a combination between good sealing properties and workability.

Claims (15)

Extruded coated substrate having a coating comprising a multimodal polyethylene produced by polymerization catalyzed by a single site catalyst and comprising at least two different C _4-12 alpha-olefins as comonomers for ethylene To The polyethylene, a) low molecular weight bicomponent copolymer of ethylene and but-1-ene; And b) high molecular weight bicomponent copolymers of ethylene and C ₅ to C ₁₂ alpha-olefins; Characterized in that it comprises a bimodal polymer comprising a, or a ') a low molecular weight polymer which is a bicomponent copolymer of ethylene and C ₄ to C ₁₂ alpha-olefins; And b ') when the low molecular weight polymer of component a') is a bicomponent copolymer of ethylene and a C ₅ to C ₁₂ alpha-olefin, it is a bicomponent copolymer of ethylene and but-1-ene, or is ethylene, but-1- High molecular weight polymers that are trimers of ene and C ₅ to C ₁₂ alpha-olefins; An extrusion coated substrate comprising a bimodal polymer comprising a. The method of claim 1, The polyethylene is two kinds selected from the group consisting of but-1-ene, hex-1-ene, 4-methyl-pent-1-ene, hept-1-ene, oct-1-ene and deck-1-ene An extrusion coated substrate, characterized in that it comprises the above alpha-olefins as comonomer to ethylene. The method of claim 2, Wherein said polyethylene comprises an ethylene butene copolymer and an ethylene hexene copolymer. delete delete The method according to any one of claims 1 to 3, The polyethylene has an molecular weight distribution (MWD) of 3 to 6, a melt flow rate (MFR ₂ ) of 5 to 20 g / l0 minutes, density is 905 to 930 kg / ㎥, characterized in that the extrusion coated substrate. delete The method according to any one of claims 1 to 3, Wherein the coating comprises low density polyethylene (LDPE). The method of claim 8, Said low density polyethylene (LDPE) forms from 15 to 35% by weight of said coating. The method according to any one of claims 1 to 3, An extrusion coated substrate, characterized in that it comprises multiple coating layers. The method according to any one of claims 1 to 3, Wherein the substrate is paper, cardboard, polyester film, cellophane, polyamide film, polypropylene film, oriented polypropylene film or aluminum foil. delete Extruding multimodal polyethylene produced by polymerization catalyzed by a single site catalyst and comprising two or more different C _4-12 alpha-olefins as comonomers for ethylene to form a polymer melt, and In the extrusion method of the coating comprising the step of coating the substrate with the melt, The polyethylene, a) low molecular weight bicomponent copolymer of ethylene and but-1-ene; And b) high molecular weight bicomponent copolymers of ethylene and C ₅ to C ₁₂ alpha-olefins; Characterized in that it comprises a bimodal polymer comprising a, or a ') a low molecular weight polymer which is a bicomponent copolymer of ethylene and C ₄ to C ₁₂ alpha-olefins; And b ') when the low molecular weight polymer of component a') is a bicomponent copolymer of ethylene and a C ₅ to C ₁₂ alpha-olefin, it is a bicomponent copolymer of ethylene and but-1-ene, or is ethylene, but-1- High molecular weight polymers that are trimers of ene and C ₅ to C ₁₂ alpha-olefins; Characterized in that it comprises a bimodal polymer comprising, extrusion method of the coating. The method of claim 13, Wherein said polyethylene is produced in a two-step process comprising a loop reactor followed by a gas phase reactor. The method according to claim 13 or 14, Wherein said polyethylene is blended with low density polyethylene (LDPE) prior to extrusion.

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